Apparatus for removing pulp from a treatment vessel



A ix-i128, 1959 1 'M. ALKAN EI N 6 APPARATUS FoR REMOVING PULP FROM A TREATMENT VESSEL Filed Kay 6, 1 957 2 Sheets-Sheet 1 FIG. I

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INVENTOR. J0 m ms J; "(mug M. J. JALKANEN 2,884,146 APPARATUS FOR REMOVING PULP FROM A TREATMENT 'VESSEL April' 28, 1959 2 Sheets-Sheet 2 Filed May 6; ,1957

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nvvmox. "i1 1 Johannes Jamal-2K United States Patent lice APPARATUS FOR REMOVING PULP FROM A TREATMENT VESSEL Matti Johannes Jalkanen, Rauma, Finland Application May 6, 1957, Serial No. 657,406 Claims priority, application Finland November 22, 1956 Claims. (Cl. 214-17) The present invention relates to new and novel apparatus for removing pulp from a treatment vessel; and more particularly to such apparatus wherein cutting means is provided for cutting the pulp above a certain level in the vessel, and conveyor means is provided adjacent the cutting means for removing the cut pulp from the vessel.

In accordance with modern technological developments in the treatment of certain pulps, such as wood pulp, chemical pulp or sugar beet pulp for example, vertically extending hollow treatment vessels or towers are employed for treating the pulp. In such towers, the pulp is caused to move upwardly from the bottom of the tower to a point near the top of the tower where an outlet opening is provided in the tower through which the treated pulp passes out of the tower. As the pulp moves upwardly in the tower, and is allowed to thicken so that it no longer flows freely, and accordingly it is necessary to provide ameans for removing the pulp from the vessel.

In prior art apparatus, the pulp is usually removed from the treatment tower by means of rotating scraper devices, as for example, an arm secured to and rotated by a shaft mounted in the center of the tower. These rotating arms force the pulp from the center of the vessel to the inner wall of the tower, and then gradually urge the pulp toward the outlet opening in thetower. One of the major drawbacks of such devices is that the pulp is'not removed evenly across the cross-sectional area of the tower. Accordingly, some portions of the pulp remain in the tower longer than other portions resulting in nonuniform treatment of the pulp, which is very undesirable. In addition, considerable power is required in driving the scraper device in order to knead the pulp adjacent the inner surface of the tower.

In the present invention, a rotating cutting means is provided which cuts off the top portion of the pulp as it rises above a certain level in the tower. The pulp is cut evenly across the cross-sectional area of the tower, and is collected on a flat portion provided on the upper surface of the cutting means. A conveyor is positioned above the cutting means and closely adjacent thereto for moving the cut pulp from the flat portion of the cutting means" to the outlet opening in the tower. With this arrangement, the pulp is removed evenly from the, tower so that all portions of the pulp remain in the tower for substantially the same amount of time, thereby providing uniform treatment of the pulp.' Furthermore, the power required to drive the cutting means is substantially less than thatrequired to drive prior art scraper devices.

An object of the present invention is to provide a new and novel apparatus for removing pulp from a treatment vessel wherein the pulp is removed evenly across the cross-sectional area of the tower, I

Another object is the provision of apparatus for removing from a treatmentvesselwherein the power. required for driving the apparatus is reduced to a minimum.

' A further object is to provide apparatus for removing 2,884,146 A I Patented A 2 19 5 pulp from a treatment vessel which is simple and inexpensive in construction, yet efficient and reliable in operation. 7

Other objects and many attendant advantages of the present invention will become obvious when considered in connection with the following specification and drawings wherein:

Fig. 1 is a longitudinal section of a treatment vessel adjacent the outlet opening of the vessel,

Fig. 2 is a sectional view taken on the line II-II of Fig. 1 looking in the direction of the arrows,

Fig. 3 is a view similar to Fig. 1 showing a modification of the invention,

Fig. 4 is a sectional view taken on the line IV--IV of Fig. 3 looking in the direction of the arrows, and

Fig. 5 is an enlarged view of a portion of an arm of the apparatus.

Referring now to the drawings wherein like reference characters designate like parts throughout the several views, there is shown in Figs. 1 and 2 a preferred embodiment of the invention including a vertically extending treatment vessel or tower 10 which is hollow and substantially cylindrical in configuration. Pulp is introduced into the tower at the lower portion thereof (not shown), and is urged upward in the tower by conventional means. An outlet opening 11 is provided through the wall of the tower in the upper portion thereof, and a pipe 12 having an enlarged upper portion 13 is secured to the outer surface of the tower for conducting the treated pulp away from the tower.

A tubular shaft 15 is rotatably disposed along the longitudinal axis of tower 10, and means (not shown) is provided for rotating the shaft in a counterclockwise direction as seen in Fig. 2 during operation of the apparatus. Three substantially radially extending arms or cutting means 20 are secured to shaft 15 and extend to a point closely adjacent the inner wall of the tower. As seen in Fig. 2, the arms preferably have the configuration of sectors of a circle, in plan view, but obviously many variations inshape may be made if desired.

Referring to Fig. 5, the forward or leading edge 21 of each arm 20 in the direction of rotation is formed as a tapered cutting edge and is disposed below the lower surface 22 of the arm. The upper surface of each arm is composed of a substantially flat portion 23 and a sloping portion 24 extending from edge 21 to flat portion 23. As arms 20 rotate during operation, cutting edges 21 of each of the arms cut the pulp which has risen above the plane of rotation of the cutting edges. The cut pulp travels upward along sloping portions 24 and is collected on flat portions 23 of the arms. Since the cutting edges 21 is disposed below the lower surface 22 of each of the arms, the top surface of the pulp within the tower is allowed to rise freely after the cutting edge has passed thereover.

Referring again to Figs. 1 and '2, a conveyor means is positioned adjacent the arms and spaced slightly above the plane of rotation of the arms. The conveyor means includes a conventional screw member 30 secured to a shaft 31 and extending from a point adjacent shaft 15 through outlet opening 11 and terminating approximately over the center of enlarged portion 13 of pipe 12. One end of shaft 31 is journalled in a suitable bearing 32 secured to enlarged portion 13 of pipe 12; and the opposite end of theshaft extends through a suitable opening 33 formed through the wall of tower 10, and is secured to the drive shaft of a suitable driving means such' as an electric motor 35.; In this construction the bearings-and the driving .motor aredisposed away from and are accordingly protected from the harmful effects of any gases or steams present in the tower.

Shaft 31 is driven in the direction of arrow 36 by motor 35 during operation, and shaft is driven in the direction of arrows 37 during operation. Accordingly, points on the outer circumference of the screw 30 at the lowermost portion thereof move in a direction opposite to the direction of movement of arms adjacent thereto. As each arm passes beneath screw 30, the rotating movement of the screw prevents the collected pulp from travelling further in the direction of movement of the arm, and simultaneously causes the collected pulp to move in a lateral direction along the axis of shaft 31 such that it passes through outlet opening 11 and is conducted away from the tower through pipe 12. A small portion of the collected pulp on one arm may not pass through outlet opening 11 and may remain in the tower and be removed as the next succeeding arm passes under the screw member.

It is apparent that the outer circumference of the screw at the lowest point thereof must be positioned closely adjacent the plane of rotation of the flat portions of the arms, and the space therebetween is preferably on the order of five to ten millimeters, although the apparatus functions satisfactorily between the limits of approximately five to fifty millimeters.

Referring now to Figs. 3 and 4 which illustrate another embodiment of the invention similar to the apparatus shown in Figs. 1 and 2 and wherein like parts have been given the same reference numerals primed, screw 30 is replaced with an endless belt 40 having a plurality of normally extending projections 41 secured thereto. Belt 40 is supported on rollers 42 and 43, roller 42 being rotatably supported upon a bracket 44 secured to a beam 45 having the opposite ends thereof secured to the inner wall of the tower. Roller 43 is connected to the drive shaft of an electric motor 46 for driving the belt in the direction of arrows 47 during operation of the apparatus. The remainder of the structure of the apparatus shown in Figs. 3 and 4 is identical with that shown in Figs. 1 and 2.

It is apparent that as the arms pass beneath endless belt 40, projections 41 will engage the collected pulp on the flat portions of the upper surfaces of the arms such that the pulp is caused to move laterally outward through outlet opening 11 in the tower. The lowermost points of projections 41 are preferably spaced between five and ten millimeters above the plane of rotation of the flat portions of each of the arms, but the apparatus functions satisfactorily between the limits of approximately five to fifty millimeters.

The conveyor means of the present invention has been disclosed either as a screw or an endless belt, although other types of conveyor means may be substituted therefor as may occur to one skilled in the art. Also, more than one conveyor means may be employed if desired. The number, width, thickness and configuration as well as the rotating speed of the arms of the apparatus may also be varied in accordance with well-known design characteristics as required in any particular application. In each case, however, a cutting means must be provided which cooperates with a suitable conveyor means whereby all the pulp above a certain level in the tower is cut by the cutting means and then caused to move laterally out of the tower by the conveyor means.

With an arrangement according to the present invention, the pulp is cut evenly from the entire top surface of the pulp and is removed to the exterior of the tower. As a result, the pulp rises evenly in the vessel and all particles remain in the vessel for substantially the same amount of time resulting in uniform treatment of the pulp. The power required to drive the arms and the conveyor is reduced to a minimum since it is not necessary to knead the pulp adjacent the inner walls of the tower. Additionally, the device is simple and inexpensive in construction, yet efficient and reliable in operation.

The invention is not to be considered limited to the specific embodiments shown, but as defined within the scope of the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. Apparatus for removing pulp from a treatment vessel which comprises a hollow treatment vessel adapted to receive upwardly moving pulp therein during operation, said vessel having an outlet opening formed therein, rotating cutting means moving substantially in a plane for cutting the pulp above a certain level in said vessel, said cutting means having an upper substantially plane surface for collecting cut pulp, and conveyor means positioned above the plane of rotation of said cutting means for moving out pulp from said upper surface to said outlet opening.

2. Apparatus for removing pulp from a treatment vessel which comprises a hollow treatment vessel adapted to receive upwardly moving pulp therein during operation, said vessel having an outlet opening formed therein, a shaft rotatably disposed in the center of said vessel, said shaft having substantially radially extending cutting means secured thereto for cutting the pulp above a certain level in said vessel, said cutting means having an upper substantially plane surface for collecting cut pulp and moving in a substantially horizontal plane, conveyor means for moving out pulp from said upper surface to said outlet opening, said conveyor means being positioned above and substantially parallel to the plane of rotation of said cutting means and extending from a point adjacent the center of the vessel to said outlet opening.

3. Apparatus as defined in claim 2 wherein said conveyor means includes a screw member, and means for rotating said screw member such that the lowermost portion thereof moves in a direction opposite to the direction of movement of said cutting means.

4. Apparatus as defined in claim 2 wherein said conveyor means includes an endless belt having normally extending projections, and means for moving said endless belt such that the lower portion thereof moves outwardly from the center of said vessel to the outlet opening thereof.

5. Apparatus for removing pulp from a treatment vessel which comprises a hollow treatment vessel adapted to receive upwardly moving pulp therein during operation, said vessel having an outlet opening formed therein, a shaft rotatably disposed in the center of said vessel, said shaft having at least one substantially radially extending arm secured thereto for cutting the pulp above a certain level in said vessel, said arm having upper and lower surfaces, means for rotating said shaft such that said arm rotates in a substantially horizontal plane, said upper surface having a substantially fiat portion for collecting cut pulp, the forward edge of said arm in the direction of rotation comprising a cutting edge, and conveyor means positioned above the plane of rotation of said arm for moving cut pulp from said flat portion to said outlet opening.

6. Apparatus as defined in claim 5 wherein the cutting edge of said arm is disposed below the lower surface of said arm.

7. Apparatus as defined in claim 6 wherein the forward portion of the upper surface of said arm slopes upwardly to said substantially fiat portion.

8. Apparatus for removing pulp fnom a treatment vessel which comprises a hollow treatment vessel adapted to receive upwardly moving pulp therein during operation, said vessel having an outlet opening formed therein, a shaft rotatably disposed in the center of said vessel, said shaft having a plurality of substantially radially extending arms secured thereto for cutting the pulp above a certain level in said vessel, each of said arms having upper and lower surfaces, means for rotating said shaft such that said arms rotate in a substantially hori zontal plane, each of said upper surfaces having a sub- 0 stantially flat portion for collecting cut pulp, the forward edge of each of said arms in the direction of rotation comprising cutting edges disposed below the lower surface of the respective arms, the forward portion of the upper surface of each of said arms sloping upwardly to the substantially fiat portion of the respective arms, and conveyor means for moving out pulp from the fiat portions of each of said arms to said outlet opening, said conveyor means being positioned above and substantially parallel to the plane of rotation of said arms and extending from a point adjacent said shaft to said outlet opening.

9. Apparatus as defined in claim 8 wherein said conveyor means includes a screw member, and means for rotating said screw member such that the lowermost portion thereof moves in a direction opposite to the direction of movement of said cutting means.

References Cited in the file of this patent UNITED STATES PATENTS 650,569 Shaw May. 29, 1900 1,338,743 Lyman May 4, 1920 2,511,246 Chamberlin June 13, 1950 2,587,714 Embree et al. Mar. 4, 1952 2,719,058 Van Dusen Sept. 27, 1955 

